1. Field of the Invention
The invention relates to a display device having an element in which a light emitting material is sandwiched between electrodes (hereinafter referred to as a light emitting element).
2. Description of the Related Art
Recently, the development of a liquid crystal display device and an electroluminescent display device in which thin film transistors (TFTs) are integrated over a glass substrate has been in progress. As to each of such display devices, TFTs are manufactured over a glass substrate by thin film formation technologies, and a liquid crystal element or a light emitting element (electroluminescent (hereinafter simply referred to as EL) element) formed over various circuits configured with the thin film transistors, thus functions as a display device.
A circuit formed with TFTs has some surface irregularities, hence in forming the liquid crystal elements or the light emitting elements over the circuit, the circuit is generally planarized with an organic resin film or the like (Reference 1: Japanese Patent Laid-Open No. 9-236826). Each pixel provided for a display area of a display device includes a pixel electrode inside, and the pixel electrode is connected to a TFT through a contact hole formed in the organic resin film used for planarization.